Microbe eating spilled oil in Gulf of Mexico

A newly discovered species of microbe is breaking down oil from the BP spill in the Gulf of Mexico much faster than scientists thought possible.

The newly discovered type of oil-eating microbe, which is suddenly flourishing in the Gulf of MexicoPhoto: AP

By Nick Allen in Los Angeles

6:52PM BST 25 Aug 2010

The leaking well was plugged on July 15 and two weeks later government scientists said that half of the oil had gone.

The new microbe was found to be breaking down oil about twice as fast as expected.

Researchers discovered the new oil-eating microbe while studying the underwater dispersion of millions of gallons which escaped after the explosion of the Deepwater Horizon drilling rig in April.

It thrives in cold water in the deep sea where temperatures are around 5C (41F) and scientists said it may have adapted over time, through a process of natural selection, due to periodic leaks and natural seeps of oil in the Gulf.

When the bacteria were found to have acted on oil they consumed half of it in 1.2 to 6.1 days, giving an average of about three days. By comparison at the site of the Exxon Valdez spill in Alaska in 1989 the average "half life" was seven days.

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Around 95 per cent of the bacteria in the oil plume were the new type, while outside only five per cent were.

The microbe was discovered by a team led by Terry Hazen, of Lawrence Berkeley National Laboratory in Berkeley, California. The study was reported in the journal Science.

Hazen said:"What we know about the degradation rates fits with what we are seeing in the last three weeks. We've gone out to the sites, and we don't find any oil, but we do find the bacteria."

The researchers said it provided the first ever data on microbial activity from a deep water oil plume. It suggested "a great potential" for bacteria to help dispose of oil in the deep sea.

Environmentalists have raised fears about the giant oil spill and the effects of underwater oil on sea life. Last week a mist of tiny oil droplets 22 miles (35km) long was reported.

But the researchers said the influx of oil had profoundly altered the "microbial community." They collected more than 200 samples from 17 deep water sites between May 25 and June 2. The new microbe was found to be the dominant one and, although closely related to exisiting petroleum degrading ones, was a new species.

The team also found that the new microbe acts without significantly depleting oxygen in the water.

There have been concerns that oil-eating activity by microbes would consume large amounts of oxygen in the water and create "dead zones" which would destroy ecosystems and fisheries.

But the study found that, while oxygen saturation outside the oil plume was 67 per cent, within the plume it was still 59 per cent. A previous study published last week suggested no decrease in oxygen.

Hundreds of thousands of barrels of oil a year seep into the Gulf every year through the sea floor.

It was suggested that oil was dispersing quickly because Gulf light crude is more biodegradable than other oil types and dispersant may have speeded up nthe process.

There has been much debate about what has happened to the cloud of oil, a mile wide and 650ft high, that was drifting at 4,000ft under water.